1. Field of the Invention
The present invention relates to a retainer used in a sliding block of a linear guideway, and more particularly to a simple, low cost and easily assembled steel wire retainer for a sliding block, which has high quality and can meet the market's requirement.
2. Description of the Prior Art
Since linear transmission products are being applied more and more widely in the modern industry, various linear transmission mechanisms have widely come into human life, manufacturing factory and high science and technology instruments, such as linear guideway, ball screw, and the like. Particularly in a large-scale precision mechanism are usually installed various large and small ball screws or linear guideway systems. Although the technology for linear transmission element is developing fast, consumers still need the technology to be improved uninterruptedly. Therefore, there are still some problems to be solved. And this desire for constant improvement of technology is particular strong in many high precision mechanism-manufacturing fields that require comparative stability and quiet. Hence, the existing linear mechanism still has some technological blind spots to be improved. Retainers in the sliding block of a linear guideway generally include metal board type retainer and embedded type plastic retainer, which are described as follows:
Metal Board Type
With reference to FIGS. 1 and 2, which show the metal board type retainers disclosed by U.S. Pat. Nos. 4,253,709 and 4,747,284, both of these two patents disclose a metal retaining board that is disposed between the sliding board and the rail. The metal retaining board is made by pressing and folding process. The metal board 12 as disclosed in U.S. Pat. No. 4,253,709 is fixed on the inner surface of the sliding block 10 by screws 141 and is adapted to retain a plurality of ball grooves 14 at a time, and the metal board 12 is shaped for mating with the rail 11. However, this metal board is impractical because of the following reasons:
First, the metal board 12 is made by pressing and folding process, accordingly its production cost is relatively high.
Second, the metal board 12 is fixed on the inner surface of the sliding block 10 by screws 141, the metal board 12 must be processed to form threaded holes, and this will complicate the assembly process.
Third, loading balls 142 in the respective ball grooves 14 or adjusting the balls 142 therein requires the user to assemble and disassemble the metal board 12 repeatedly by rotating the screws 141, therefore, the efficiency of balls loading or adjusting is very low.
Fourth, the metal board 12 is likely to produce noise when the balls 142 roll on it, and the impact of the balls 142 on the metal board 12 will aggravate the noise. To overcome the abovementioned assembly problems, U.S. Pat. No. 4,749,284 discloses another type product, wherein a plurality of metal retaining boards 15 are partially embedded in the sliding block 10 for mating with the respective ball grooves 14, and the metal retaining boards 15 are used to retain the balls 142, enabling the balls 142 to abut against the rail 11. Although the retaining boards 15 are modified to be positioned in an embedded manner, and this can substantially reduce the complexity of assembly and adjustment, it still has the following problems:
First, the metal retaining boards 15 should be processed with pressing and folding, the quantity of the metal retaining boards 15 is comparatively large, and it has to make the to-be-embedded portion whose angle is very difficult to make, therefore, the production cost of these metal retaining boards 15 is relatively high.
Second, the metal boards 15 may produce noise when the balls 142 roll on it, and the noise will be aggravated by the impact of the balls 142 on the metal boards 15.
Embedded Type Plastic Retainer
Another product that can overcome the noise and the production cost problems appears on the market, as shown in FIG. 3, wherein a plurality of plastic boards 18 are embedded during the assembly of the sliding block 16 and the end caps 17 and are used to prevent the disengagement of the balls out of the balls groove. Although the plastic boards 18 are made by plastic injection molding and it can simplify the production and effectively reduce the noise, the plastic board still has the problems as follows:
First, the plastic boards 18 can't provide sufficient support strength and must cooperate with the sliding block 16 and the end caps 17, since the plastic boards 18 are embedded between the sliding block and the end caps 17, such arrangement will increase the complexity of balls loading and adjusting.
Second, the plastic board is susceptible to deformation when it is subjected to temperature changes and erosive work surrounding, furthermore, the deformation of the plastic board will interfere with the operation of the balls.
To solve the aforementioned problems, the inventor of this invention, on the basis of the accumulated experience and skills associated with the linear transmission field, develops a brand new steel wire retainer for a sliding block that is free of influence from the factors, such as material, assembly and strength.